Friday, 6 November 2009

The surface of isolated material such like polyester yarn,nylon yarn,elastomeric yarn or others synthetic material is normally not charged. When the yarn surface moves towards another material, or get frictions with others parts surface on warping machine during warping process , e.g :a yarn sheet moving on reed ,tension tube or ceramic eyelet , electrons can be transported from the surface layer of these part to the yarn sheet. This is called triboelectric effect and causes an imbalance of the electric charge of the material, the surface layer of one material becomes positively charged and the other one negatively charged. As the yarn sheet and warping parts is isolated, the charge cannot be conducted away through the yarn or parts which get friction with the yarn sheet itself, the charge is then called static electricity. The ability of the electric charge to attract one with the opposite polarity or to repel another with the same polarity may then cause problems, e.g.:Broken filaments on the yarns,hairness or the yarn sticky together.Different hardness and outer circumference in one set of warp beam when warp a textured yarn often occurred due static electricity or electro static.The most problem due electro static on the yarn sheet during warping process are :

Broken filament.

Un-even warp beam surface.

Different outer circumference in one set of warp beam,mostly for textured yarn.

Yarn hainess.

Short life time of the latch needle for the warp knitting machine used latch needle.

The charged surface of the yarn sheet can be neutralized by ionizing the air uses anti static equipment or electro static discharger (ESD),i.e. air particles are charged by positive and negative polarity.
The negatively charged air particles can then give off an electron to a positively charged particle in the surface of an isolated material, thereby neutralizing particles both in air and material. In the same way the positive air particles are neutralized by the negative particles in a charged material.
The anti static equipments uses a high voltage electrode to ionize air particles through corona discharge to both positive and negative polarity.

Picture 2,showing the ESD installed below the yarn sheet before and after main reed ,before the yarn sheet warp onto the beam.

Wherever ESD are used to control static discharge,the effectiveness of an ESD system depends on the type of ionizers used and how they are installed on warp knitting machines. Measuring the static in the area
before and after a ESD is installed helps determine how well the system performs.
It’s also important to periodically monitor the area or process to detect unacceptable levels of charge accumulation and verify that the system is working properly.

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comments:

If i have the anti static rod installed on my wrapping machine, does that mean that the material i produce from my knitting machine will have an anti-static affect? Meaning that the fabric wont generate electric when rubbing them together.

The anti static device installed on the warping machine use for to reduce event to eliminate the electro static on the yarn sheet due a friction between yarn and other parts on the warping machine which can be influence to the yarn quality such a broken filament,hairnes,slub and fluff.

On the knitting machine,depend of material which use on the knitting machine,the fabric produce on knitting machine can be also contains electro static due a friction between yarns and knitting elements during knitting process not because of rubbing them together.

Basically the electro static produces by frictions of different kind material.